Surgical pump

ABSTRACT

This invention relates to a surgical pump primarily designed for the pumping of blood, as in open-heart surgery or for pumping blood through a &#39;&#39;&#39;&#39;kidney machine,&#39;&#39;&#39;&#39; but also particularly adapted for other surgical uses, such as pumping dialycate in a &#39;&#39;&#39;&#39;kidney machine,&#39;&#39;&#39;&#39; or the like; and is characterized by the fact that it provides direct and continuous volumetric adjustment from 0 to the maximum size of the pump even while in use; is small in size and light-weight; is readily adjustable as to the force applied to the liquid being pumped, and has independently adjustable timing of the diastole and sistole portions of a pumping cycle.

[54] SURGICAL PUMP [76] Inventor: Karl Shlll, 38171 A sford Way, Fremont, Calif. 9453 6 4 22 Filed: o1.21, 1971 21 Appl.No.: 191,207

[52] US. Cl. ..4l7/326, l28/DlG. 3, 128/214 R,

[51] int. c1; ..F04h 35/02. [58] Field orsearcli ..4l7/383-389, 394, 417/395, 478, 326, 479; 128/1 D, DIG. 3

[56] References Cited V UNITED STATES PATENTS cycle.

1111 1 51 Apr. 3, 1973 3,478,695 11/1969 G oranson ..4l7/394 Primary Examiner-William L. Fre'eh Assistant Examiner-John T. Winbu rn Attorney-Robyn Wilcox 57] ABSTRACT This invention relates to a surgical pump primarily designed for the pumping of blood, as in open-heart surgery or for. pumping blood through a kidney machine," but also particularly adapted for other surgical uses, such as pumping dialycate in a kidney machine, or the like; and is characterized by the fact that it provides direct and continuous volumetric adjustment from 0 to the maximum size of the pump even while in use; is small in size and light-weight; is

readily adjustable as to the force applied to the liquid being pumped, and has independently adjustable timing of the diastole and sistole portions of a pumping 14 Claims, 8 Drawing Figures PAIENIEUW ms SHEET 1 BF 2 em sfiiii ATTORIIEY PATENTEU 3 i973 sum 2 [IF 2 Ill! Warn 5%??? ATTORNEY SURGICAL PUMP BACKGROUND OF THE INVENTION the prime requisites of such a pump is that it have low platelet destruction and low hemolysis. The first pumps were quite destructive of blood cells, because there was a rubbing, or grinding, effect which burst the cells. This was overcome by passing the blood through a sterile tube, one end of which received blood from the body and the other end of which returned it to the body or treating apparatus; providing a short section in the tube delineated by one-way valves; and applying a pulsing pressure to the walls of the delineated section of the tube as by the periodic compression from a hydraulic source. Examples of this type of pump are shown in the patents to Birtwell, US. Pat. No. 3,099,260, Wilson, U.S. Pat. No. 3,551,076, and Huffman, et al., US. Pat. No. 3,550,162. The present invention utilizes a pump of this general nature in which an easily replaced and disposable sterile tube having a short pump section which is separated from the balance of the tube by a one-way flow valve'at each end, each of which allows flow in the same direction, and systematically and continually applying a squeezing pressure around the tube the pump of the present invention, thereby avoiding the danger of electrical power failure. The unit is small and light and, therefore, may be clamped to the operating table, a gumey, or other equipment near the patient as maybe required.

Since the pump of the present invention has adjustable timing, adjustable pressure and independently adjustable diastolic and sistolic timing, a single pump may be used for the full spectrum of surgical needs, from a newborn baby to a well-developed athlete. Since the adjustments can be made while the pump is in opera- I tion, the pump has built-in compensation for a change in the physical condition of the patient during an operatron.

and alternately applying a vacuum around the tube so as to suck in more blood. The present invention differs from the prior art in that the sterile blood tube is inserted through the pump and the hydraulic fluid which applies the pumping'and vacuum pressure thereto doesnot come in contact with the tube, so that the pump and its contents does not need to be sterile; and the blood tube does not need to be sealed to the pump to complete the assembly. Also, preferably, an improved type of one-way valve is used which will do less damage to the blood cells.

One of the advantages of the present invention, in its preferred form, lies in the fact that the volume of blood, or other liquid, pumped in each stroke and thereby, indirectly, the blood pumped, is infinitely variable from 0 to the maximum capacity of the pump and adjustments can be made easily and accurately while the pump is in operation. Another advantage is that the force applied to the blood conduit is also variable over a considerable range, and adjustments may also be made while the pump is in operation; Additionally, both the duration of the diastole and the sistole strokes are independently adjustable and again the adjustments can bemade while the pump is in operatiomThe pump is driven' and controlled without electrical power, thereby reducing hazards from the breakdown of elec trical equipment ora failure inthe electrical system or power supply, and cumbersome equipment at the operating site. .The pump is preferably powered by water pressure from the water system of the hospital.

Water pressuretaken directly from the cold water line is a more reliable source of power than electricity, as hospitalsv generally have an independent water storage tank on the roof to guarantee a supply of water at all times. The pressure exerted by water from this system is much greater than that needed for the operation of OBJECTS It is a primary object of the invention to provide a small, light-weight surgical pump which can be used the diastole and sistole functions.

It is still afurther object of the present invention to provide a pump suitable for heart bypass use which has low blood platelet destruction andhemolysis and which accordinglywill do little damage to the blood being recirculated by it.

It is still a further object of the present invention to provide a surgical pump which, in itself, does not have to be sterilized, since only the tube through which the blood or other liquid passes needs to be sterile, and that tube is easily inserted through the pumping section of the present invention and may be disposed of after use.

These and other objects of the present invention will be apparent from the specification which follows, taken -in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view on a reduced scale of the preferred form of pump of the present invention.

FIG. 2 is a cross-sectional view of the power section of the pump of FIG. 1, such as taken along the plane indicated by the line 2-2 of FIGS. 1 and 3.

FIG. 3 is a cross-sectional view of the control section of the pump, such as taken along the plane indicated by the line 33 of FIGS. 1 and 2.

FIG. 4 is a cross-sectional view of the pump section of the pump of the present invention, such as taken along the plane indicated by the line 4-4 of FIG. 3.

FIG. 5 is an enlarged view of the one-way control valve. 104 which controls the flow of pressure liquid during the pumping stroke.

FIG. 6 is an enlargedview of the one-way control valve 107 which controls the flow of pressure liquid during the suction stroke.

" FIG. 7 is an enlarged cross-sectional view of the control valve shown in FIG. 5, such as takenalong the plane indicated by the line 7-7 of FIG;

The pump of the present invention comprises three major assemblies which are integrally connected by structure, passageways and functions. They are: (A) power unit (B) control section 100, and (C) pump section 180. It should be kept in mind that these three sections are contained in a single unit as shown in FIG. 1, but for ease of understanding, they should be discussed separately, and for purposes of construction, are built as three units which are readily assembled, or conversely disassembled for repair or modification.

A. POWER UNIT The power unit is best shown in FIG. 2, which is a cross-sectional view through the length of the power unit 20. As indicated above, the preferable source of power is the conventional water supply which may be conducted to the unit through a flexible tube 21, coming from any suitable source, such as the tap water from the hospital piping, a storage tank on the roof, or the like. Since there may be many variations in pressure of fluid to be supplied to the unit, it is preferred that the tube 21 be provided with a suitable pressure-reducing valve 22 which can be adjusted by some suitable means, such as handle 23. It is believed unnecessary to describe the construction of the pressure-reducing valve 22, as many suitable devices are available on the market. It should be noted that the pump operates on only a small part of the normal available pressure, and that normal fluctuations in pressure from hospital usage still allows a much greater pressure than is needed for pump operation. However, in most procedures it is very important to have the pump operating consistently. Thus, while the pressure reducing valve is not necessary for pump operation, it can be assumed that it would be used in any surgical procedure. Further, since solids in the water supply could affect operation of the power unit, it normally would be advisable to provide a filter 29 somewhere in the water supply for the pump.

The power unit preferably comprises a cylinder 30, the upper end of which is capped by a cap 31 that is rigidly held in the casing 101 of the control unit 100 to be described hereafter. The cap 31 is attached to the cylinder 30 by any suitable means, such as studs 32. The cap section 31 can be rigidly held in the casing 101 of the control unit by any suitable means, but preferably by a dog pointed screw 42 extending through the end wall of the casing 101 and engaging an annular groove 33 in the cap 31, thereby holding it tightly in the casing 101 but permitting it to be adjusted to any radial position desired. Incidentally, it can be noted that I prefer to connect the various assemblies together by means of a dog pointed screw engaging annular slots, with access to the slot by the screw from the nearest convenient surface, as such construction permits rapid assembly or disassembly by a technician without undue attention to the radial disposition of the parts, or adjustment thereof.

The pump of the present invention can be mounted on an operating table, a gurney, or any other suitable place, by means of a bracket 24 which has a pair of parallel flanges 27 and 28 and an adjusting screw 25 threaded into the flange 28. The bracket 24 is affixed to the device in any suitable manner, but preferably is attached to one end of the casing 101 of the control section 100 (Section B) by suitable studs 26, as shown in FIG. 1. An adjusting screw 25 threaded into flange 28 and in opposition to flange 27 enables an operator to attach the pump to any convenient flat surface.

A shaped flexible diaphragm 45 is clamped between the cylinder 30 and its cap 31, preferably being shaped to form a rolling contact with the interior walls'40, 41, respectively, of the cylinder 30 and cap 31. The diaphragm 45 is held against collapsing by providing piston-shaped followers 46 and 47 which are fastened together by some suitable means, such as studs 48. As shown in FIG. 2, the cap 31 adjacent to cylinder 30 is hollowed to form a cap section 31 of the same diameter as that of the interior wall 40 of the cylinder 30. Thus, the piston-like member 46, 47, which clamps the diaphragm 45 between them, can pass from the cylinder to the cap without difficulty and prevent collapsing or distortion of the diaphragm 45. Since the pistons 46, 47 are almost the diameter of the cylinder, relatively little pressure is exerted against the diaphragm and it can be light and quite flexible. The upper piston member 47 is provided with an internal bore 49 which forms a spring seat for a compression spring 50. The other end of the spring 50 is seated in a central bore, or flow passage, 35 formed in the end section of cap 31 and axially aligned with the bore 49. This central bore 35 communicates with an annular groove 36 in the outer wall of the cap 31 by means ofa diametric passageway 37 (see also FIG. 3). It should be noted here that a force transmission liquid fills cup 34, bore 35, passageways 37 and annular groove 36 and other communicating passageways and chambers to be described in Sections B and C. Thus, when a superior force is applied against the piston member 46 and diaphragm 45, the piston rises into the chamber 34, thereby forcing liquid contained in the chamber 34 and bore 35 out through the passageway 37 and annular groove 36. When the ,force below the piston is removed, the spring 37 forces the piston downwardly, thereby sucking previously expelled liquid back through the groove 36 and passageway 37 into the chamber 34.

The lower end of the cylinder 30 is plugged by a plug 60 threaded into it, or otherwise rigidly secured thereto. This plug 60 will be drilled to provide the inlet and outlet passages leading into the interior of the cylinder 30 and an axial hole 54 to guide a piston rod 51 which carries a spool control valve 63 to be described shortly. Liquid from the tube 21 enters through an inlet passageway 61, thence around an annular groove 62 in the spool valve 63, and thence into passageway 64 leading into the interior of the cylinder 30, assuming the spool valve is in the lower position shown in FIG. 2, which is the position it will assume for the in-flow ofliquid under pressure. At the proper time, when the spool valve 63 is forced upwardly, liquid within the cylinder 30 can flow from the power unit by means of a passageway 66, annular groove 67 in spool valve 63 and outlet port 68 and is forced to do so by the spring 50 operating the piston 46, 47 and diaphragm 45. The spool valve 63 moves within an internal bore 65 of the plug 60 and is slidably mounted on the piston rod 51. It, the spool valve 63, is adjusted to either its upper or lower operative positions only at the very extreme end of piston 51 by means of a collar 53 to be described more in detail hereafter. The spool valve 63 is provided with a pair of V-notches 69, 70 which, when the spool valve is in the lower position shown in FIG. 2, lie adjacent the end of the plug 60.

A piston rod 51 is set in the diaphragm followers 46, 47 which form the piston, being held rigidly therein by any suitable means, such as set screw 52 threaded through an aperture in the piston member 46 and set into an indentation in the piston rod 51. The piston rod 51 extends through the suitable passageway 65 in the plug 60, and is sealed against leakage by a suitable O- ring 73.

The enlarged bore 65 within the plug 60 carries the loosely fitting spool valve 63 slidably mounted on the piston rod 51, and is sealed against leakage between the inlet annular groove 62 and the outlet annular groove 67 by suitable O-rings 71 and'72. A vent (illustrated by dotted lines) between the upper end of bore 65 and atmosphere permits escape of air trapped between the 0- rings 71 and 73.

Cooperating with the V-notches 69 and 70 in the lower end of the spool valve 63 is a garter spring 80 which lies within and is longitudinally restrained by annular cup 81 formed in the upper end of a cap 82. Since the longitudinal, or axial, movement of the garter spring 80 is prevented by the lower end of the plug 60 and the lower wall of cup 81, it cooperates with the notches 69, 70 in the spool valve 63 to give a snap action of the spool valve 63 in its movement between its two operative positions. It is obvious that the garter spring 80 will hold the spool valve 73 in any adjusted position until overcome by some greater force. The adjusting force is supplied by the collar 53 pinned to the lower end of the piston rod 51. When this collar engages the inner end of the bore 74, it lifts the spool valve from the position shown in FIG. 2 to its raised position in which the passage of fluid between inlet port 61 and inlet passageway 64 is blocked by the spool valve, and the outlet passageway 66 is in communication with outletport 68 through annular groove 67. It is held in this position by the garter spring 80 until the downward movement of the piston rod 51 causes the collar 53 thereon to engage the upper end of a pin 90 carried by the lower end of the spool valve 63, as hereinafter described, and thereby snap it to its lowermost position.

The cap 82 is attached to the lower endof the plug 60 by any suitable means, such as studs 83, and is provided with a relatively large bore 84 which is large enough to loosely embrace the lower end of the spool valve 63. The lower end of the spool valveis provided with a relatively large bore 74, large enough to encircle the collar 53 pinned or otherwise rigidly secured to the lower end of the piston rod 51, preferably without contact between the inner face of the bore 74 and the collar 53. In order to provide the adjustments desired, it is necessary to prevent rotation of the spool valve 63 and this is readily accomplished by means of a slot 75 in the wall of the lower bore 74 with which registers a pin 85 threaded into the wall of the cap 82. The pin permits axial movement of the spool valve 63 but blocks rotation thereof.

The interior wall 74 of the bore at the lower end of the spool valve 63 is threaded to receive a threaded pin 90 which is rigidly secured in a cup member 91 by any suitable means, such as pin 92. Preferably, as shown in groove 62, the outlet groove 64, the two V-notches 69,

70, will operate with the garter spring 80, to give snap movement only to the spool valve 63. The garter spring and its cooperating grooves 69 and 70 prevent slow movement of the spool valve 63, and thereby avoid the possibility of the valve being held in an intermediate position in which both the inlet and outlet ports are partially open. The combination of the garter spring and its associated V-notches causes a snap action of the spool valve, so that it is snapped from either operative position. It will be readily seen that the adjustment of the cup 91 will control the position of the piston assembly to move from the outlet position to the inlet position, and that the position of the collar 53 will determine when the spool valve is raised from the outlet position to the inlet position. Thus, an operator is readily able to determine the length of the power stroke 'and consequently the amount of liquid that will be pumped by each stroke.

B. CONTROL SECTION The control section is contained in a casing 101 which, preferably is mounted perpendicularly to the power section 20, the upper cap 31 of the power section being located in a bore 102 in an intermediate location in the casing 101. The bore '102 has a passageway 103 leading from the annular groove 36 in the cap 31 through a one-way control valve 104 described in connection with FIG. 5, and thence into a passageway 105 which extends lengthwise of the casing 101. The passageway 105 communicates with an annular groove 183 formed in the pump body' to be described in Section C by a suitable cross-passage 106. As shown in FIG. 3, the passageway 105 extends almost to the opposite end of the casing 101, and likewise communcates with a one-way control valve 107, and thence through'passageway 108 leading back into the annular groove 36 previously mentioned. It should be noted that the one-way valves 104 and 107 operate in opposite directions, so that during the pumping, or diastolic, stroke the entrapped force transmitting liquid will pass from chamber 34 in the pumping section to passageway 105 and thence into the pump section 180,

but cannot go into passage 108 and through the check valve 107; and on the suction, or systolic, stoke, the one-way feature of the valve 104 prevents return of the fluid through it, but permits it through the control valve 107. The construction of the check valves is quite control section can be changed from time to time by removing the cap 109 and either removing or adding fluid to this section. It should also be noted that both of these valves are adjustable in order to control the rate of flow through them, so that either a rapid or a slow movement of the pump can be secured in either the pumping or suction portion of a cycle.

The control valve 104 is shown in FIG. 5. It comprises a stem 120 at the outer end of which is a handle 121. The valve stem 120 rather tightly fits in a transverse bore 1 in the control casing 101. The stem has an angular groove 122, which is adapted to receive a dog pointed set screw 123 which enables the stem 120 to be turned in the bore 110 but to prevent its axial adjustment therein. The stem 120 is also provided with a pair of small grooves 124 and 125, in which are seated flexible O-rings 126 and 127 which firmly seat against the wall of the bore 110 and thereby provide a liquid seal therebetween.

Registering with the passageway 103, the stem 120 has a port 128 which communicates with a central bore 129 in the stem. Preferably, the bore 129 terminates in a flaring end to receive the conical section of the stem of the cooperating one-way valve member 135, as shown in FIG. 5. It will be noted that the bore 128 extends radially from the central bore 129, as shown in FIG. 7. Registering with the outer end of the bore 128 is a helical groove 130. Thus, rotation of the stem 120 can present a blank wall 131 to the passageway 103, or a completely free entrance into the bore 128, or any intermediate setting in between.

Cooperating with the stem 120 is a valve member 135 which comprises a central collar 136 and a pair of oppositely extending guide pins 137 and 138 considerably smaller than the bores in which they lie. Preferably, the collar 136 is beveled to fit firmly against the flared end of the passageway 129 and, when fitted with a sealing O-ring 140, will prevent back flow into passageway 128 and thence into the interior of cap 31. A light compression spring 139, seated between the end of the bore 1 10 and the collar 136, biases the collar 136 against the end of the stem 120 and when in that position, will form a water-tight seal against passage of water from the channel 105 into channel 103 and thence into the pumping section. By turning the stem 120, the amount of liquid that can pass through the port 128 can be very carefully regulated, thereby determining the length of the pumping stroke. Obviously, if the port is of small cross-sectional area, as by the small part of the helix registering with the passageway 103, the action of the entire pump will be slowed down as the piston assembly in the pumping section (members 46, 47 and piston rod 51) can move only slowly as it is assumed that water will be contained in the control section and that is incompressible.

The control valve 107 associated with the suction passageway 108 is similar in many respects to the first mentioned control valve and comprises a stem 150 which can be set to any angular position by a handle 151. It is held firmly seated in a bore 111 formed in the casing 101 by means of a dog pointed set screw 153 which registers with a groove 152 in the stem. While the stem 150 could be interchangeable with 120, in which case it would need only one O-ring 157 and cooperating groove 155, as it is only necessary to seal the valve assembly from leakage to outside of the chamber, while the valve 104 has to be sealed both against leakage to the outside of the chamber but also to reach into the passageway 105. The stem 150 is provided with a radial bore 158 communicating with a central axial bore 159 and with a helical groove 160 which registers with the suction passageway 108. However, the cooperating one-way valve member must necessarily be quite different. Again there is a valve member 165 which comprises a collar 166 and opposed guide stems 167 and 168. In this case, however, the collar 166 is adjacent the upper end of the valve member and the upper stem 167 is quite short, as it should penetrate the aperture into the flow passage and is biased against that aperture by a weak compression spring 169. In this case, the upper face of the collar is beveled and the upper end of the bore 111, in which the valve assembly fits, is flared so that the collar 166 will form a liquidtight seal when abutting against the flared end wall of the bore 111, which is the valve seat.

Preferably, the collars 136 and 166 of the two control valves 104 and 107, respectively, can be provided with O-rings and 170, respectively, which seat against the flared bore 129 of the first one-way check valve or the flared end of the bore 111 in the suction one-way check valve. In each control valve the rotation of the stem 120 or by means of its handle 121 or 151 will determine the cross-sectional area available for the passage of the force transmitting fluid, preferably water, during the pumping and suction strokes of the apparatus, and therefore determines the length of time required for the completion of each stroke. It is thus seen that both the diastolic and sistolic portions ofa pumping cycle can be independently controlled as required by the operator.

It should be mentioned here that a very satisfactory pump could omit the two control valves 104 and 107, or it might be a single control valve without any oneway feature. In the first instance, there would be no control of the speed with which the force transmitting fluid from the power section to the pump section could be controlled independently of the setting of the pressure reducing valve. In that case, it is assumed the entire control section of the preferred form of the invention could be omitted, and the chamber 34 of the power section would communicate directly with the pump chamber to be described in the next section. In the second instance, a single adjustable flow control valve would be interposed between the power chamber 34 and the pump chamber and the valve stems 135 and eliminated. In that event, the rate of flow from the power chamber 34 to the pump chamber, and vice versa, could be controlled by the setting of the valve, but the rate on both the pumping and suction strokes would necessarily be the same. By providing the two control valves and their associated one-way valve stems 135 and 165 working in opposite directions, an operator is enabled to provide independent control of the timing of the two strokes. However, if such a feature is not desired, the pump could be simplified by omitting one or both of the control valves (and both one-way valve stems) and the pump would operate satisfactorily as a pump without the independent control feature which I prefer.

c. PUMP SECTION The pump section l80 comprises a tubular casing 181 that has a relatively-tight fit withthe bore 112 in the casing 101 (FIGS. 3 and 4). The casing 181 can be locked in position by a set screw, not shown, threaded into a suitable aperture in the casing 101 and registering with an annular groove 182 in the casing 181. This permits rotation of the pump member 180 if desired,

but not longitudinal movement. The casing 181 is formed with an annular groove 183 which registers with passageway 106 when the pump is in proper position. A plurality of radial orifices 184 lead from the annular groove 183 into the interior portion of the cylindrical casing 181'. A pair of O-rings 185 and 186 lie in grooves 187, 188 in the casing 181, thereby forming membrane 190 are preferably sealed, as by means of folding over a conical collar 191, placing a truncated conical thimble 192 over the foldeditube and collar, and the whole rigidly sealed by a cap 193 which is threaded onto suitable threads formed on the casing 181. A- gasket 195 compressed between the conical col-' lar 191 and the end of the casing 181 seals the tubular membrane 190 against leakage. Preferably, as shown in FIG. 4, the ends of the casing 191. are restricted for a slight distance, thereby providing an elongated, cylindrical chamber 194 throughout the length of the easing, and lying between the wall of the casing 181 and tubular membrane 190. Thus, throughout most of its length within the casing 181, the outer silastic tubing 190 will not lie against the wall of the casing but will be embraced by the fluid of the control section which will completely encompass the tube throughout most of its length within the casing at all times. Thisconstruction permits the rapid and equalized transmission of pressure to the entire length of the pump chamber on the pump stroke but also the rapid and equalized vacuum thereto on the suction stoke.

It is believed obvious that the operation of the power section, through the medium of the liquid entrapped in the control section, will cause the pulsation of fluid in the chamber 194 that lies within the casing 181 and outside of the tubular sleeve 190. During the pumping stroke, the tube 190 will be squeezed inwardly and during the suction stroke it will expand outwardly beyond I the position shown in FIG. 4. The amount of squeezing will be determined by the, length of stroke'in the power section, and the speed with which that squeezing takes place is determined by the setting of the control valve shown in FIG. 5 and the speed of restoration by the setting of control valve-107 shown in FIG. 6.

The blood, or other fluid, to be pumped passes through. a suitable silastic tube 200. Preferably, the tube 200 will-be of a length slightly greater than the length of casing 181 and will be provided at each end with conical nipples 201 over which the blood supply tubes of suitable size, selected by the surgeon, an be forced. The surgeon has the option at the time of surgery of selecting a suitable orifice size for the pump by simply cutting off the nipple at the location where its diameter is desired. The tube 200 is provided with a pair of one-way valves 202 which can be of any suitable construction. However, I prefer to use tricuspid valves,

such as shown in FIG. 8. Bicuspid valves are known in the art and have been found more suitable for use in pumping blood than the older ball-type valves. Bicuspid valves comprise a single pair of lips which normally lie together but which open as liquid is pumped through them. However, I have found that a tricuspid valve, such as shown in FIG. 8, is better for pumping blood, as it opens more widely and does less damage to the blood cells. As shown in FIG. 8, such a valve comprises three pairs of lips 203 at the axis of the tube, the lips normally being compressed lightly together but openin" to substantially the full circumference of the tube as liquid is forced through them. Normally, such a valve would be made on a short stem 204, separate from the blood tube 200, and later cemented into place. Any force whichwould push-the pumped liquid backwardly through the tube is prevented, as such force only seals the lips more tightly together. It is believed obvious that the two valves 202 are located outside. of the pumping chamber but within the pumping section 180, preferably without the casing 181 but within the lock nutsl93. 1

Preferably, the blood tube would be prepared by taking a length of silastic tubing 200 longer than spacing of the two nipples 201; cementing the one-way valves 202 in the proper location; and then cementing the .two nipples within the tube leaving a length of tube 200 a hospital can store a desired supply of sterile pump sections, any one of which can. be used at a moments notice. When a surgeon desires to use a pump, he will cut off the end of the tube and can fold it back to form a cuff 205 around the base of the nipple. Preferably, one end of the sealed and sterile blood tube 200 will be provided with a lanyard 206 as it is easier to pull such a tube through a rather tightlyfitting aperture, such as that provided by the tubular membrane 190, than to push it through. After the blood tube is inserted in the pump chamber and the ends cut off, the tubes that connect the pump to the patient, or to treating devices, can be pushed over the nipples 201, and the device is ready for use. i I

In most conditions it can be assumed that the length of tube between the input nipple 201 and its associated one-way valve 202 is longer than at the output end, to

provide, a small blood storage reservoir between the nipple and the one-way valve.

D. SUMMARY briefly summarize it. The force which can be applied to ing valve 22 in the inlet conduit 21. In most instances water pressure should be reduced in order to use the pump in open-heart surgery, or other times when it is necessary to pump blood for a patient. The total amount of blood to be pumped in each stroke is determined by the setting of the collar 53 on piston rod 51 and the setting of the cup 91 with respect to the spool valve 63. That is, a greater or lesser amount of blood can be pumped in each cycle as controlled by these settings, as they control the limit of response for the action of the spool valve 63. Hence, for a small child, the strokes will be relatively short, while for a mature and athletic adult they could be quite long to provide for a pumping of a considerable amount of blood with each cycle of operation. It should be noted that in no case should the stroke be sufficient to totally collapse (occlude) the pump tube, as this would submit the blood to direct compression against opposite walls of the tube and thereby rupture the blood cells so they cannot carry oxygen (hemolysis) and cause the platelets to destruct (causing coagulation). The speed of the diastolic and sistolic portions of a pumping cycle are controlled by the respective settings of the one-way check valves 104 and 107 which are settable independently, so that it is possible to have a rapid diastolic stroke and a slow sistolic one, or vice versa. It can be noted that the force transmitting liquid contained within the control chambers is small but can never come in contact with the tube through which the blood is circulating. It is, therefore, impossible for any unsterile condition of the pump to affect the sterility of blood within the tube 200. Thus, the pump does not have to be completely sterilized (although it is assumed that it will always be cleaned) and the only portion of the apparatus that does have to be sterilized, is the tube 200 and the tubes which connect it to the body of the patient. Since it is anticipated that the blood tube will be furnished sealed and sterile, it may be placed in the pump and stored, ready for use in an emergency.

Since power to operate the pump is supplied by water under pressure, the doctor can rely upon the water supply within the hospital, and power failure would not be the problem that it is when relying on an electric system.

It is believed that several advantages are inherent in a pump of this type, for adjustments can readily be made, even while the pump is in operation. Thus, an operating assistant can change the settings of the pump so that it will operate in synchronism with the heart of the patient, and the supply of blood with each beat can be modified as required. it is also possible, by means of a pump of this kind, to use it as a partial bypass after surgery to permit the heart to operate at reduced capacity while healing takes place without interfering with the normal blood supply of the patient. It is believed that these and other advantages of the pump of the present invention will be obvious to those skilled in the art. It should also be noted that it is possible to provide the control chamber with a plurality of pump chambers, so that it could operate not only to pump blood but also some other liquid for example, also pump dialysate and blood to an artificial kidney. Accordingly, it is intended that all modifications which lie within the scope of the underlying inventive concepts are to be included within the scope of the claims and the invention is not limited to the particular forms herein shown and described.

lclaim:

1. A surgical pump comprising:

. a cylinder,

2. a tubular flexible diaphragm within said cylinder, said tubular diaphragm being adapted to embrace a blood supply tube provided with a pair of one way valves therein to permit flow therethrough in one direction only,

3. means for sealing the ends of said diaphragm to the ends of said cylinder and thereby providing a space between the cylinder and said tubular diaphragm,

4. a chamber adapted to contain a pressure transmitting liquid,

5. a passageway connecting said chamber and the space between said cylinder and said tubular diaphragm; and

6. means for sequentially applying a positive and then a negative pressure to the liquid in said chamber.

2. The apparatus of claim 1 comprising also a flow regulating valve in said passageway.

3. The apparatus of claim 1 wherein there is a second passageway between said chamber and the space between said cylinder and said tubular diaphragm, and comprising also an adjustable flow regulating valve in each of said passageways, a one-way valve in one of said passageways permitting flow only from said chamber, and a one-way valve in the other of said passageways permitting flow only into said chamber.

4. The apparatus of claim 1 wherein the means for applying a positive and then a negative pressure to the liquid in said chamber comprises:

1. a cylinder,

2. a flexible diaphragm within said cylinder, said diaphragm forming one wall of said chamber,

3. an inlet into said cylinder on the other side of said diaphragm, an outlet from said cylinder on said other side of said diaphragm,

5. a valve means operated by movement of said diaphragm for opening said inlet while closing said outlet and then opening said outlet and closing said inlet.

5. The apparatus of claim 4 comprising also an adjustable means for adjusting the amount of liquid admitted to said cylinder with each stroke thereof.

6. A surgical pump comprising:

A. a power section including 1. a cylinder adapted to receive a liquid under pressure, 2. a flexible diaphragm within said cylinder, 3. an inlet into said cylinder on one side of said diaphragm, an outlet from said cylinder on the same side of said diaphragm, 5. means for biasing said diaphragm toward said one side thereof,

means for supplying liquid under pressure to said inlet, and 7. valve means operated by movement of said diaphragm for opening said inlet and closing said outlet and then closing said inlet and closing said outlet;

1. an intermediate control chamber adapted to hold a liquid, one wall of said chamber being said diaphragm,

2. an outlet from said chamber,

3. a one-way flow-control valve in said outlet, 4. an inlet to said chamber, 5. a one-way flow control valve in said inlet, and 6. means for introducing a liquid into said chamber; and C. a pumping section comprising:

1. a cylinder,

2. a cylindrical flexible diaphragm within said cylinder, 3. means for sealing the ends of said cylindrical diaphragm to the ends of said cylinder and thereby providing an open-ended cylinder adapted to receive a flexible tube carrying blood, said tube being provided with one-way check valves, and 4. passageways into said chamber communicating with said one-way outlet and said one-way inlet valves inthe control chamber.

7. The apparatus of claim 6 wherein the outlet valve from said control chamber 'has an adjustable port whereby the volume of liquid passing through said valve in any interval of time can be controlled.

8. The apparatus of claim 6 wherein the inlet valve into said control chamber comprises an adjustable port whereby the volume of liquid passing through said port in any given interval of time can be controlled.

9. The apparatus of claim 6 wherein the one-way outlet valve and the one-way inlet valve have adjustable ports wherein the volume of liquid passing through said ports in any given interval of time can be adjusted independently.

.10. The apparatus of claim 6 comprising also means for selectively changing the operation of said first-mentioned valve means to vary the volume of liquidunder pressure admitted into said cylinder.

11. The apparatus of claim 6 wherein the flexible diaphragm within said cylinder of said power section is clamped between a pair of washers, and wherein said valve means operated by movement of said diaphragm comprises a rod carried by said washers, a spool valve controlling said inlet and said outlet slidably mounted on said rod, and means fixed to said rod for operating said spool valve at the extremes of movement of said rod.

12. The apparatus of claim 1 1 comprising also means for causing said valve means to snap from one position to another.

13. A blood pump comprising:

1. a cylinder,

2. a tubular flexible diaphragm within said cylinder,

3. means for sealing the ends of said diaphragm to the ends of said cylinder and thereby providing a space between the cylinder and said tubular diaphragm,

4. a tube for conducting a flow of blood embraced within said tubular diaphragm,

5. a pair of one-way valves for permitting flow in one direction only in said tube and located outside of the diaphragm,

6. a chamber adapted to hold a pressure transmitting liquid,

7. a passageway from said chamber to the space between said cylinder and said tubular diaphragm,

8. means for introducing a liquid into said chamber,

and 9. means for sequentially applying pressure to the liquid in said chamber and then applying a vacuum thereto.

meeting adjacent the axis of said tube. 

1. A surgical pump comprising:
 1. a cylinder,
 2. a tubular flexible diaphragm within said cylinder, said tubular diaphragm being adapted to embrace a blood supply tube provided with a pair of one-way valves therein to permit flow therethrough in one direction only,
 3. means for sealing the ends of said diaphragm to the ends of said cylinder and thereby providing a space between the cylinder and said tubular diaphragm,
 4. a chamber adapted to contain a pressure transmitting liquid,
 5. a passageway connecting said chamber and the space between said cylinder and said tubular diaphragm; and
 6. means for sequentially applying a positive and then a negative pressure to the liquid in said chamber.
 2. The apparatus of claim 1 comprising also a flow regulating valve in said passageway.
 2. a tubular flexible diaphragm within said cylinder, said tubular diaphragm being adapted to embrace a blood supply tube provided with a pair of one-way valves therein to permit flow therethrough in one direction only,
 2. a flexible diaphragm within said cylinder, said diaphragm forming one wall of said chamber,
 2. a tubular flexible diaphragm within said cylinder,
 2. a flexible diaphragm within said cylinder,
 2. a cylindrical flexible diaphragm within said cylinder,
 2. an outlet from said chamber,
 3. means for sealing the ends of said cylindrical diaphragm to the ends of said cylinder and thereby providing an open-ended cylinder adapted to receive a flexible tube carrying blood, said tube being provided with one-way check valves, and
 3. an inlet into said cylinder on one side of said diaphragm,
 3. a one-way flow-control valve in said outlet,
 3. means for sealing the ends of said diaphragm to the ends of said cylinder and thereby providing a space between the cylinder and said tubular diaphragm,
 3. The apparatus of claim 1 wherein there is a second passageway between said chamber and the space between said cylinder and said tubular diaphragm, and comprising also an adjustable flow regulating valve in each of said passageways, a one-way valve in one of said passageways permitting flow only from said chamber, and a one-way valve in the other of said passageways permitting flow only into said chamber.
 3. an inlet into said cylinder on the other side of said diaphragm,
 3. means for sealing the ends of said diaphragm to the ends of said cylinder and thereby providing a space between the cylinder and said tubular diaphragm,
 4. a chamber adapted to contain a pressure transmitting liquid,
 4. The apparatus of claim 1 wherein the means for applying a positive and then a negative pressure to the liquid in said chamber comprises:
 4. an outlet from said cylInder on said other side of said diaphragm,
 4. a tube for conducting a flow of blood embraced within said tubular diaphragm,
 4. an outlet from said cylinder on the same side of said diaphragm,
 4. passageways into said chamber communicating with said one-way outlet and said one-way inlet valves in the control chamber.
 4. an inlet to said chamber,
 5. The apparatus of claim 4 comprising also an adjustable means for adjusting the amount of liquid admitted to said cylinder with each stroke thereof.
 5. a one-way flow control valve in said inlet, and
 5. means for biasing said diaphragm toward said one side thereof,
 5. a valve means operated by movement of said diaphragm for opening said inlet while closing said outlet and then opening said outlet and closing said inlet.
 5. a pair of one-way valves for permitting flow in one direction only in said tube and located outside of the diaphragm,
 5. a passageway connecting said chamber and the space between said cylinder and said tubular diaphragm; and
 6. means for sequentially applying a positive and then a negative pressure to the liquid in said chamber.
 6. a chamber adapted to hold a pressure transmitting liquid,
 6. A surgical pump comprising: A. a power section including
 6. means for supplying liquid under pressure to said inlet, and
 6. means for introducing a liquid into said chamber; and C. a pumping section comprising:
 7. valve means operated by movement of said diaphragm for opening said inlet and closing said outlet and then closing said inlet and closing said outlet; B.
 7. The apparatus of claim 6 wherein the outlet valve from said control chamber has an adjustable port whereby the volume of liquid passing through said valve in any interval of time can be controlled.
 7. a passageway from said chamber to the space between said cylinder and said tubular Diaphragm,
 8. means for introducing a liquid into said chamber, and
 8. The apparatus of claim 6 wherein the inlet valve into said control chamber comprises an adjustable port whereby the volume of liquid passing through said port in any given interval of time can be controlled.
 9. The apparatus of claim 6 wherein the one-way outlet valve and the one-way inlet valve have adjustable ports wherein the volume of liquid passing through said ports in any given interval of time can be adjusted independently.
 9. means for sequentially applying pressure to the liquid in said chamber and then applying a vacuum thereto.
 10. The apparatus of claim 6 comprising also means for selectively changing the operation of said first-mentioned valve means to vary the volume of liquid under pressure admitted into said cylinder.
 11. The apparatus of claim 6 wherein the flexible diaphragm within said cylinder of said power section is clamped between a pair of washers, and wherein said valve means operated by movement of said diaphragm comprises a rod carried by said washers, a spool valve controlling said inlet and said outlet slidably mounted on said rod, and means fixed to said rod for operating said spool valve at the extremes of movement of said rod.
 12. The apparatus of claim 11 comprising also means for causing said valve means to snap from one position to another.
 13. A blood pump comprising:
 14. The apparatus of claim 13 wherein the one-way valves in said blood tube comprise three pairs of lips meeting adjacent the axis of said tube. 